Muffin pan



FIG. 1 is a perspective view of a muffin pan showing our new design;

FIG. 2 is an end elevational view thereof, the opposite end being identical thereto;

FIG. 3 is a top plan view thereof;

FIG. 4 is a side elevational view thereof, the opposite side being identical thereto; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a muffin pan, as shown and described. 